1 /* 2 * linux/fs/reiserfs/xattr.c 3 * 4 * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com> 5 * 6 */ 7 8 /* 9 * In order to implement EA/ACLs in a clean, backwards compatible manner, 10 * they are implemented as files in a "private" directory. 11 * Each EA is in it's own file, with the directory layout like so (/ is assumed 12 * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory, 13 * directories named using the capital-hex form of the objectid and 14 * generation number are used. Inside each directory are individual files 15 * named with the name of the extended attribute. 16 * 17 * So, for objectid 12648430, we could have: 18 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access 19 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default 20 * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type 21 * .. or similar. 22 * 23 * The file contents are the text of the EA. The size is known based on the 24 * stat data describing the file. 25 * 26 * In the case of system.posix_acl_access and system.posix_acl_default, since 27 * these are special cases for filesystem ACLs, they are interpreted by the 28 * kernel, in addition, they are negatively and positively cached and attached 29 * to the inode so that unnecessary lookups are avoided. 30 * 31 * Locking works like so: 32 * Directory components (xattr root, xattr dir) are protectd by their i_mutex. 33 * The xattrs themselves are protected by the xattr_sem. 34 */ 35 36 #include <linux/reiserfs_fs.h> 37 #include <linux/capability.h> 38 #include <linux/dcache.h> 39 #include <linux/namei.h> 40 #include <linux/errno.h> 41 #include <linux/gfp.h> 42 #include <linux/fs.h> 43 #include <linux/file.h> 44 #include <linux/pagemap.h> 45 #include <linux/xattr.h> 46 #include <linux/reiserfs_xattr.h> 47 #include <linux/reiserfs_acl.h> 48 #include <asm/uaccess.h> 49 #include <net/checksum.h> 50 #include <linux/stat.h> 51 #include <linux/quotaops.h> 52 #include <linux/security.h> 53 54 #define PRIVROOT_NAME ".reiserfs_priv" 55 #define XAROOT_NAME "xattrs" 56 57 58 /* Helpers for inode ops. We do this so that we don't have all the VFS 59 * overhead and also for proper i_mutex annotation. 60 * dir->i_mutex must be held for all of them. */ 61 #ifdef CONFIG_REISERFS_FS_XATTR 62 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 63 { 64 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 65 return dir->i_op->create(dir, dentry, mode, NULL); 66 } 67 #endif 68 69 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, int mode) 70 { 71 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 72 return dir->i_op->mkdir(dir, dentry, mode); 73 } 74 75 /* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr 76 * mutation ops aren't called during rename or splace, which are the 77 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's 78 * better than allocating another subclass just for this code. */ 79 static int xattr_unlink(struct inode *dir, struct dentry *dentry) 80 { 81 int error; 82 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 83 84 reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, 85 I_MUTEX_CHILD, dir->i_sb); 86 error = dir->i_op->unlink(dir, dentry); 87 mutex_unlock(&dentry->d_inode->i_mutex); 88 89 if (!error) 90 d_delete(dentry); 91 return error; 92 } 93 94 static int xattr_rmdir(struct inode *dir, struct dentry *dentry) 95 { 96 int error; 97 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 98 99 reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, 100 I_MUTEX_CHILD, dir->i_sb); 101 dentry_unhash(dentry); 102 error = dir->i_op->rmdir(dir, dentry); 103 if (!error) 104 dentry->d_inode->i_flags |= S_DEAD; 105 mutex_unlock(&dentry->d_inode->i_mutex); 106 if (!error) 107 d_delete(dentry); 108 dput(dentry); 109 110 return error; 111 } 112 113 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 114 115 static struct dentry *open_xa_root(struct super_block *sb, int flags) 116 { 117 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 118 struct dentry *xaroot; 119 if (!privroot->d_inode) 120 return ERR_PTR(-ENODATA); 121 122 mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); 123 124 xaroot = dget(REISERFS_SB(sb)->xattr_root); 125 if (!xaroot) 126 xaroot = ERR_PTR(-ENODATA); 127 else if (!xaroot->d_inode) { 128 int err = -ENODATA; 129 if (xattr_may_create(flags)) 130 err = xattr_mkdir(privroot->d_inode, xaroot, 0700); 131 if (err) { 132 dput(xaroot); 133 xaroot = ERR_PTR(err); 134 } 135 } 136 137 mutex_unlock(&privroot->d_inode->i_mutex); 138 return xaroot; 139 } 140 141 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 142 { 143 struct dentry *xaroot, *xadir; 144 char namebuf[17]; 145 146 xaroot = open_xa_root(inode->i_sb, flags); 147 if (IS_ERR(xaroot)) 148 return xaroot; 149 150 snprintf(namebuf, sizeof(namebuf), "%X.%X", 151 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 152 inode->i_generation); 153 154 mutex_lock_nested(&xaroot->d_inode->i_mutex, I_MUTEX_XATTR); 155 156 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 157 if (!IS_ERR(xadir) && !xadir->d_inode) { 158 int err = -ENODATA; 159 if (xattr_may_create(flags)) 160 err = xattr_mkdir(xaroot->d_inode, xadir, 0700); 161 if (err) { 162 dput(xadir); 163 xadir = ERR_PTR(err); 164 } 165 } 166 167 mutex_unlock(&xaroot->d_inode->i_mutex); 168 dput(xaroot); 169 return xadir; 170 } 171 172 /* The following are side effects of other operations that aren't explicitly 173 * modifying extended attributes. This includes operations such as permissions 174 * or ownership changes, object deletions, etc. */ 175 struct reiserfs_dentry_buf { 176 struct dentry *xadir; 177 int count; 178 struct dentry *dentries[8]; 179 }; 180 181 static int 182 fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 183 u64 ino, unsigned int d_type) 184 { 185 struct reiserfs_dentry_buf *dbuf = buf; 186 struct dentry *dentry; 187 WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex)); 188 189 if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) 190 return -ENOSPC; 191 192 if (name[0] == '.' && (name[1] == '\0' || 193 (name[1] == '.' && name[2] == '\0'))) 194 return 0; 195 196 dentry = lookup_one_len(name, dbuf->xadir, namelen); 197 if (IS_ERR(dentry)) { 198 return PTR_ERR(dentry); 199 } else if (!dentry->d_inode) { 200 /* A directory entry exists, but no file? */ 201 reiserfs_error(dentry->d_sb, "xattr-20003", 202 "Corrupted directory: xattr %s listed but " 203 "not found for file %s.\n", 204 dentry->d_name.name, dbuf->xadir->d_name.name); 205 dput(dentry); 206 return -EIO; 207 } 208 209 dbuf->dentries[dbuf->count++] = dentry; 210 return 0; 211 } 212 213 static void 214 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) 215 { 216 int i; 217 for (i = 0; i < buf->count; i++) 218 if (buf->dentries[i]) 219 dput(buf->dentries[i]); 220 } 221 222 static int reiserfs_for_each_xattr(struct inode *inode, 223 int (*action)(struct dentry *, void *), 224 void *data) 225 { 226 struct dentry *dir; 227 int i, err = 0; 228 loff_t pos = 0; 229 struct reiserfs_dentry_buf buf = { 230 .count = 0, 231 }; 232 233 /* Skip out, an xattr has no xattrs associated with it */ 234 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 235 return 0; 236 237 reiserfs_write_unlock(inode->i_sb); 238 dir = open_xa_dir(inode, XATTR_REPLACE); 239 if (IS_ERR(dir)) { 240 err = PTR_ERR(dir); 241 reiserfs_write_lock(inode->i_sb); 242 goto out; 243 } else if (!dir->d_inode) { 244 err = 0; 245 reiserfs_write_lock(inode->i_sb); 246 goto out_dir; 247 } 248 249 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 250 251 reiserfs_write_lock(inode->i_sb); 252 253 buf.xadir = dir; 254 err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); 255 while ((err == 0 || err == -ENOSPC) && buf.count) { 256 err = 0; 257 258 for (i = 0; i < buf.count && buf.dentries[i]; i++) { 259 int lerr = 0; 260 struct dentry *dentry = buf.dentries[i]; 261 262 if (err == 0 && !S_ISDIR(dentry->d_inode->i_mode)) 263 lerr = action(dentry, data); 264 265 dput(dentry); 266 buf.dentries[i] = NULL; 267 err = lerr ?: err; 268 } 269 buf.count = 0; 270 if (!err) 271 err = reiserfs_readdir_dentry(dir, &buf, 272 fill_with_dentries, &pos); 273 } 274 mutex_unlock(&dir->d_inode->i_mutex); 275 276 /* Clean up after a failed readdir */ 277 cleanup_dentry_buf(&buf); 278 279 if (!err) { 280 /* We start a transaction here to avoid a ABBA situation 281 * between the xattr root's i_mutex and the journal lock. 282 * This doesn't incur much additional overhead since the 283 * new transaction will just nest inside the 284 * outer transaction. */ 285 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 286 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 287 struct reiserfs_transaction_handle th; 288 err = journal_begin(&th, inode->i_sb, blocks); 289 if (!err) { 290 int jerror; 291 reiserfs_mutex_lock_nested_safe( 292 &dir->d_parent->d_inode->i_mutex, 293 I_MUTEX_XATTR, inode->i_sb); 294 err = action(dir, data); 295 jerror = journal_end(&th, inode->i_sb, blocks); 296 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 297 err = jerror ?: err; 298 } 299 } 300 out_dir: 301 dput(dir); 302 out: 303 /* -ENODATA isn't an error */ 304 if (err == -ENODATA) 305 err = 0; 306 return err; 307 } 308 309 static int delete_one_xattr(struct dentry *dentry, void *data) 310 { 311 struct inode *dir = dentry->d_parent->d_inode; 312 313 /* This is the xattr dir, handle specially. */ 314 if (S_ISDIR(dentry->d_inode->i_mode)) 315 return xattr_rmdir(dir, dentry); 316 317 return xattr_unlink(dir, dentry); 318 } 319 320 static int chown_one_xattr(struct dentry *dentry, void *data) 321 { 322 struct iattr *attrs = data; 323 return reiserfs_setattr(dentry, attrs); 324 } 325 326 /* No i_mutex, but the inode is unconnected. */ 327 int reiserfs_delete_xattrs(struct inode *inode) 328 { 329 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 330 if (err) 331 reiserfs_warning(inode->i_sb, "jdm-20004", 332 "Couldn't delete all xattrs (%d)\n", err); 333 return err; 334 } 335 336 /* inode->i_mutex: down */ 337 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 338 { 339 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 340 if (err) 341 reiserfs_warning(inode->i_sb, "jdm-20007", 342 "Couldn't chown all xattrs (%d)\n", err); 343 return err; 344 } 345 346 #ifdef CONFIG_REISERFS_FS_XATTR 347 /* Returns a dentry corresponding to a specific extended attribute file 348 * for the inode. If flags allow, the file is created. Otherwise, a 349 * valid or negative dentry, or an error is returned. */ 350 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 351 int flags) 352 { 353 struct dentry *xadir, *xafile; 354 int err = 0; 355 356 xadir = open_xa_dir(inode, flags); 357 if (IS_ERR(xadir)) 358 return ERR_CAST(xadir); 359 360 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 361 xafile = lookup_one_len(name, xadir, strlen(name)); 362 if (IS_ERR(xafile)) { 363 err = PTR_ERR(xafile); 364 goto out; 365 } 366 367 if (xafile->d_inode && (flags & XATTR_CREATE)) 368 err = -EEXIST; 369 370 if (!xafile->d_inode) { 371 err = -ENODATA; 372 if (xattr_may_create(flags)) 373 err = xattr_create(xadir->d_inode, xafile, 374 0700|S_IFREG); 375 } 376 377 if (err) 378 dput(xafile); 379 out: 380 mutex_unlock(&xadir->d_inode->i_mutex); 381 dput(xadir); 382 if (err) 383 return ERR_PTR(err); 384 return xafile; 385 } 386 387 /* Internal operations on file data */ 388 static inline void reiserfs_put_page(struct page *page) 389 { 390 kunmap(page); 391 page_cache_release(page); 392 } 393 394 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 395 { 396 struct address_space *mapping = dir->i_mapping; 397 struct page *page; 398 /* We can deadlock if we try to free dentries, 399 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 400 mapping_set_gfp_mask(mapping, GFP_NOFS); 401 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 402 if (!IS_ERR(page)) { 403 kmap(page); 404 if (PageError(page)) 405 goto fail; 406 } 407 return page; 408 409 fail: 410 reiserfs_put_page(page); 411 return ERR_PTR(-EIO); 412 } 413 414 static inline __u32 xattr_hash(const char *msg, int len) 415 { 416 return csum_partial(msg, len, 0); 417 } 418 419 int reiserfs_commit_write(struct file *f, struct page *page, 420 unsigned from, unsigned to); 421 422 static void update_ctime(struct inode *inode) 423 { 424 struct timespec now = current_fs_time(inode->i_sb); 425 if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink || 426 timespec_equal(&inode->i_ctime, &now)) 427 return; 428 429 inode->i_ctime = CURRENT_TIME_SEC; 430 mark_inode_dirty(inode); 431 } 432 433 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 434 { 435 int err = 0; 436 struct dentry *dentry, *xadir; 437 438 xadir = open_xa_dir(inode, XATTR_REPLACE); 439 if (IS_ERR(xadir)) 440 return PTR_ERR(xadir); 441 442 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 443 dentry = lookup_one_len(name, xadir, strlen(name)); 444 if (IS_ERR(dentry)) { 445 err = PTR_ERR(dentry); 446 goto out_dput; 447 } 448 449 if (dentry->d_inode) { 450 reiserfs_write_lock(inode->i_sb); 451 err = xattr_unlink(xadir->d_inode, dentry); 452 reiserfs_write_unlock(inode->i_sb); 453 update_ctime(inode); 454 } 455 456 dput(dentry); 457 out_dput: 458 mutex_unlock(&xadir->d_inode->i_mutex); 459 dput(xadir); 460 return err; 461 } 462 463 464 /* Generic extended attribute operations that can be used by xa plugins */ 465 466 /* 467 * inode->i_mutex: down 468 */ 469 int 470 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 471 struct inode *inode, const char *name, 472 const void *buffer, size_t buffer_size, int flags) 473 { 474 int err = 0; 475 struct dentry *dentry; 476 struct page *page; 477 char *data; 478 size_t file_pos = 0; 479 size_t buffer_pos = 0; 480 size_t new_size; 481 __u32 xahash = 0; 482 483 if (get_inode_sd_version(inode) == STAT_DATA_V1) 484 return -EOPNOTSUPP; 485 486 reiserfs_write_unlock(inode->i_sb); 487 488 if (!buffer) { 489 err = lookup_and_delete_xattr(inode, name); 490 reiserfs_write_lock(inode->i_sb); 491 return err; 492 } 493 494 dentry = xattr_lookup(inode, name, flags); 495 if (IS_ERR(dentry)) { 496 reiserfs_write_lock(inode->i_sb); 497 return PTR_ERR(dentry); 498 } 499 500 down_write(&REISERFS_I(inode)->i_xattr_sem); 501 502 reiserfs_write_lock(inode->i_sb); 503 504 xahash = xattr_hash(buffer, buffer_size); 505 while (buffer_pos < buffer_size || buffer_pos == 0) { 506 size_t chunk; 507 size_t skip = 0; 508 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 509 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 510 chunk = PAGE_CACHE_SIZE; 511 else 512 chunk = buffer_size - buffer_pos; 513 514 page = reiserfs_get_page(dentry->d_inode, file_pos); 515 if (IS_ERR(page)) { 516 err = PTR_ERR(page); 517 goto out_unlock; 518 } 519 520 lock_page(page); 521 data = page_address(page); 522 523 if (file_pos == 0) { 524 struct reiserfs_xattr_header *rxh; 525 skip = file_pos = sizeof(struct reiserfs_xattr_header); 526 if (chunk + skip > PAGE_CACHE_SIZE) 527 chunk = PAGE_CACHE_SIZE - skip; 528 rxh = (struct reiserfs_xattr_header *)data; 529 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 530 rxh->h_hash = cpu_to_le32(xahash); 531 } 532 533 err = __reiserfs_write_begin(page, page_offset, chunk + skip); 534 if (!err) { 535 if (buffer) 536 memcpy(data + skip, buffer + buffer_pos, chunk); 537 err = reiserfs_commit_write(NULL, page, page_offset, 538 page_offset + chunk + 539 skip); 540 } 541 unlock_page(page); 542 reiserfs_put_page(page); 543 buffer_pos += chunk; 544 file_pos += chunk; 545 skip = 0; 546 if (err || buffer_size == 0 || !buffer) 547 break; 548 } 549 550 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 551 if (!err && new_size < i_size_read(dentry->d_inode)) { 552 struct iattr newattrs = { 553 .ia_ctime = current_fs_time(inode->i_sb), 554 .ia_size = new_size, 555 .ia_valid = ATTR_SIZE | ATTR_CTIME, 556 }; 557 558 reiserfs_write_unlock(inode->i_sb); 559 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 560 down_write(&dentry->d_inode->i_alloc_sem); 561 reiserfs_write_lock(inode->i_sb); 562 563 err = reiserfs_setattr(dentry, &newattrs); 564 up_write(&dentry->d_inode->i_alloc_sem); 565 mutex_unlock(&dentry->d_inode->i_mutex); 566 } else 567 update_ctime(inode); 568 out_unlock: 569 up_write(&REISERFS_I(inode)->i_xattr_sem); 570 dput(dentry); 571 return err; 572 } 573 574 /* We need to start a transaction to maintain lock ordering */ 575 int reiserfs_xattr_set(struct inode *inode, const char *name, 576 const void *buffer, size_t buffer_size, int flags) 577 { 578 579 struct reiserfs_transaction_handle th; 580 int error, error2; 581 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 582 583 if (!(flags & XATTR_REPLACE)) 584 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 585 586 reiserfs_write_lock(inode->i_sb); 587 error = journal_begin(&th, inode->i_sb, jbegin_count); 588 if (error) { 589 reiserfs_write_unlock(inode->i_sb); 590 return error; 591 } 592 593 error = reiserfs_xattr_set_handle(&th, inode, name, 594 buffer, buffer_size, flags); 595 596 error2 = journal_end(&th, inode->i_sb, jbegin_count); 597 if (error == 0) 598 error = error2; 599 reiserfs_write_unlock(inode->i_sb); 600 601 return error; 602 } 603 604 /* 605 * inode->i_mutex: down 606 */ 607 int 608 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 609 size_t buffer_size) 610 { 611 ssize_t err = 0; 612 struct dentry *dentry; 613 size_t isize; 614 size_t file_pos = 0; 615 size_t buffer_pos = 0; 616 struct page *page; 617 __u32 hash = 0; 618 619 if (name == NULL) 620 return -EINVAL; 621 622 /* We can't have xattrs attached to v1 items since they don't have 623 * generation numbers */ 624 if (get_inode_sd_version(inode) == STAT_DATA_V1) 625 return -EOPNOTSUPP; 626 627 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 628 if (IS_ERR(dentry)) { 629 err = PTR_ERR(dentry); 630 goto out; 631 } 632 633 down_read(&REISERFS_I(inode)->i_xattr_sem); 634 635 isize = i_size_read(dentry->d_inode); 636 637 /* Just return the size needed */ 638 if (buffer == NULL) { 639 err = isize - sizeof(struct reiserfs_xattr_header); 640 goto out_unlock; 641 } 642 643 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 644 err = -ERANGE; 645 goto out_unlock; 646 } 647 648 while (file_pos < isize) { 649 size_t chunk; 650 char *data; 651 size_t skip = 0; 652 if (isize - file_pos > PAGE_CACHE_SIZE) 653 chunk = PAGE_CACHE_SIZE; 654 else 655 chunk = isize - file_pos; 656 657 page = reiserfs_get_page(dentry->d_inode, file_pos); 658 if (IS_ERR(page)) { 659 err = PTR_ERR(page); 660 goto out_unlock; 661 } 662 663 lock_page(page); 664 data = page_address(page); 665 if (file_pos == 0) { 666 struct reiserfs_xattr_header *rxh = 667 (struct reiserfs_xattr_header *)data; 668 skip = file_pos = sizeof(struct reiserfs_xattr_header); 669 chunk -= skip; 670 /* Magic doesn't match up.. */ 671 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 672 unlock_page(page); 673 reiserfs_put_page(page); 674 reiserfs_warning(inode->i_sb, "jdm-20001", 675 "Invalid magic for xattr (%s) " 676 "associated with %k", name, 677 INODE_PKEY(inode)); 678 err = -EIO; 679 goto out_unlock; 680 } 681 hash = le32_to_cpu(rxh->h_hash); 682 } 683 memcpy(buffer + buffer_pos, data + skip, chunk); 684 unlock_page(page); 685 reiserfs_put_page(page); 686 file_pos += chunk; 687 buffer_pos += chunk; 688 skip = 0; 689 } 690 err = isize - sizeof(struct reiserfs_xattr_header); 691 692 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 693 hash) { 694 reiserfs_warning(inode->i_sb, "jdm-20002", 695 "Invalid hash for xattr (%s) associated " 696 "with %k", name, INODE_PKEY(inode)); 697 err = -EIO; 698 } 699 700 out_unlock: 701 up_read(&REISERFS_I(inode)->i_xattr_sem); 702 dput(dentry); 703 704 out: 705 return err; 706 } 707 708 /* 709 * In order to implement different sets of xattr operations for each xattr 710 * prefix with the generic xattr API, a filesystem should create a 711 * null-terminated array of struct xattr_handler (one for each prefix) and 712 * hang a pointer to it off of the s_xattr field of the superblock. 713 * 714 * The generic_fooxattr() functions will use this list to dispatch xattr 715 * operations to the correct xattr_handler. 716 */ 717 #define for_each_xattr_handler(handlers, handler) \ 718 for ((handler) = *(handlers)++; \ 719 (handler) != NULL; \ 720 (handler) = *(handlers)++) 721 722 /* This is the implementation for the xattr plugin infrastructure */ 723 static inline const struct xattr_handler * 724 find_xattr_handler_prefix(const struct xattr_handler **handlers, 725 const char *name) 726 { 727 const struct xattr_handler *xah; 728 729 if (!handlers) 730 return NULL; 731 732 for_each_xattr_handler(handlers, xah) { 733 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 734 break; 735 } 736 737 return xah; 738 } 739 740 741 /* 742 * Inode operation getxattr() 743 */ 744 ssize_t 745 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 746 size_t size) 747 { 748 const struct xattr_handler *handler; 749 750 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 751 752 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 753 return -EOPNOTSUPP; 754 755 return handler->get(dentry, name, buffer, size, handler->flags); 756 } 757 758 /* 759 * Inode operation setxattr() 760 * 761 * dentry->d_inode->i_mutex down 762 */ 763 int 764 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 765 size_t size, int flags) 766 { 767 const struct xattr_handler *handler; 768 769 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 770 771 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 772 return -EOPNOTSUPP; 773 774 return handler->set(dentry, name, value, size, flags, handler->flags); 775 } 776 777 /* 778 * Inode operation removexattr() 779 * 780 * dentry->d_inode->i_mutex down 781 */ 782 int reiserfs_removexattr(struct dentry *dentry, const char *name) 783 { 784 const struct xattr_handler *handler; 785 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 786 787 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 788 return -EOPNOTSUPP; 789 790 return handler->set(dentry, name, NULL, 0, XATTR_REPLACE, handler->flags); 791 } 792 793 struct listxattr_buf { 794 size_t size; 795 size_t pos; 796 char *buf; 797 struct dentry *dentry; 798 }; 799 800 static int listxattr_filler(void *buf, const char *name, int namelen, 801 loff_t offset, u64 ino, unsigned int d_type) 802 { 803 struct listxattr_buf *b = (struct listxattr_buf *)buf; 804 size_t size; 805 if (name[0] != '.' || 806 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 807 const struct xattr_handler *handler; 808 handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr, 809 name); 810 if (!handler) /* Unsupported xattr name */ 811 return 0; 812 if (b->buf) { 813 size = handler->list(b->dentry, b->buf + b->pos, 814 b->size, name, namelen, 815 handler->flags); 816 if (size > b->size) 817 return -ERANGE; 818 } else { 819 size = handler->list(b->dentry, NULL, 0, name, 820 namelen, handler->flags); 821 } 822 823 b->pos += size; 824 } 825 return 0; 826 } 827 828 /* 829 * Inode operation listxattr() 830 * 831 * We totally ignore the generic listxattr here because it would be stupid 832 * not to. Since the xattrs are organized in a directory, we can just 833 * readdir to find them. 834 */ 835 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 836 { 837 struct dentry *dir; 838 int err = 0; 839 loff_t pos = 0; 840 struct listxattr_buf buf = { 841 .dentry = dentry, 842 .buf = buffer, 843 .size = buffer ? size : 0, 844 }; 845 846 if (!dentry->d_inode) 847 return -EINVAL; 848 849 if (!dentry->d_sb->s_xattr || 850 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 851 return -EOPNOTSUPP; 852 853 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 854 if (IS_ERR(dir)) { 855 err = PTR_ERR(dir); 856 if (err == -ENODATA) 857 err = 0; /* Not an error if there aren't any xattrs */ 858 goto out; 859 } 860 861 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 862 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 863 mutex_unlock(&dir->d_inode->i_mutex); 864 865 if (!err) 866 err = buf.pos; 867 868 dput(dir); 869 out: 870 return err; 871 } 872 873 static int reiserfs_check_acl(struct inode *inode, int mask) 874 { 875 struct posix_acl *acl; 876 int error = -EAGAIN; /* do regular unix permission checks by default */ 877 878 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 879 880 if (acl) { 881 if (!IS_ERR(acl)) { 882 error = posix_acl_permission(inode, acl, mask); 883 posix_acl_release(acl); 884 } else if (PTR_ERR(acl) != -ENODATA) 885 error = PTR_ERR(acl); 886 } 887 888 return error; 889 } 890 891 static int create_privroot(struct dentry *dentry) 892 { 893 int err; 894 struct inode *inode = dentry->d_parent->d_inode; 895 WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); 896 897 err = xattr_mkdir(inode, dentry, 0700); 898 if (err || !dentry->d_inode) { 899 reiserfs_warning(dentry->d_sb, "jdm-20006", 900 "xattrs/ACLs enabled and couldn't " 901 "find/create .reiserfs_priv. " 902 "Failing mount."); 903 return -EOPNOTSUPP; 904 } 905 906 dentry->d_inode->i_flags |= S_PRIVATE; 907 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 908 "storage.\n", PRIVROOT_NAME); 909 910 return 0; 911 } 912 913 #else 914 int __init reiserfs_xattr_register_handlers(void) { return 0; } 915 void reiserfs_xattr_unregister_handlers(void) {} 916 static int create_privroot(struct dentry *dentry) { return 0; } 917 #endif 918 919 /* Actual operations that are exported to VFS-land */ 920 const struct xattr_handler *reiserfs_xattr_handlers[] = { 921 #ifdef CONFIG_REISERFS_FS_XATTR 922 &reiserfs_xattr_user_handler, 923 &reiserfs_xattr_trusted_handler, 924 #endif 925 #ifdef CONFIG_REISERFS_FS_SECURITY 926 &reiserfs_xattr_security_handler, 927 #endif 928 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 929 &reiserfs_posix_acl_access_handler, 930 &reiserfs_posix_acl_default_handler, 931 #endif 932 NULL 933 }; 934 935 static int xattr_mount_check(struct super_block *s) 936 { 937 /* We need generation numbers to ensure that the oid mapping is correct 938 * v3.5 filesystems don't have them. */ 939 if (old_format_only(s)) { 940 if (reiserfs_xattrs_optional(s)) { 941 /* Old format filesystem, but optional xattrs have 942 * been enabled. Error out. */ 943 reiserfs_warning(s, "jdm-2005", 944 "xattrs/ACLs not supported " 945 "on pre-v3.6 format filesystems. " 946 "Failing mount."); 947 return -EOPNOTSUPP; 948 } 949 } 950 951 return 0; 952 } 953 954 int reiserfs_permission(struct inode *inode, int mask) 955 { 956 /* 957 * We don't do permission checks on the internal objects. 958 * Permissions are determined by the "owning" object. 959 */ 960 if (IS_PRIVATE(inode)) 961 return 0; 962 963 #ifdef CONFIG_REISERFS_FS_XATTR 964 /* 965 * Stat data v1 doesn't support ACLs. 966 */ 967 if (get_inode_sd_version(inode) != STAT_DATA_V1) 968 return generic_permission(inode, mask, reiserfs_check_acl); 969 #endif 970 return generic_permission(inode, mask, NULL); 971 } 972 973 static int xattr_hide_revalidate(struct dentry *dentry, struct nameidata *nd) 974 { 975 return -EPERM; 976 } 977 978 static const struct dentry_operations xattr_lookup_poison_ops = { 979 .d_revalidate = xattr_hide_revalidate, 980 }; 981 982 int reiserfs_lookup_privroot(struct super_block *s) 983 { 984 struct dentry *dentry; 985 int err = 0; 986 987 /* If we don't have the privroot located yet - go find it */ 988 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 989 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 990 strlen(PRIVROOT_NAME)); 991 if (!IS_ERR(dentry)) { 992 REISERFS_SB(s)->priv_root = dentry; 993 dentry->d_op = &xattr_lookup_poison_ops; 994 if (dentry->d_inode) 995 dentry->d_inode->i_flags |= S_PRIVATE; 996 } else 997 err = PTR_ERR(dentry); 998 mutex_unlock(&s->s_root->d_inode->i_mutex); 999 1000 return err; 1001 } 1002 1003 /* We need to take a copy of the mount flags since things like 1004 * MS_RDONLY don't get set until *after* we're called. 1005 * mount_flags != mount_options */ 1006 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1007 { 1008 int err = 0; 1009 struct dentry *privroot = REISERFS_SB(s)->priv_root; 1010 1011 err = xattr_mount_check(s); 1012 if (err) 1013 goto error; 1014 1015 if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) { 1016 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 1017 err = create_privroot(REISERFS_SB(s)->priv_root); 1018 mutex_unlock(&s->s_root->d_inode->i_mutex); 1019 } 1020 1021 if (privroot->d_inode) { 1022 s->s_xattr = reiserfs_xattr_handlers; 1023 reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s); 1024 if (!REISERFS_SB(s)->xattr_root) { 1025 struct dentry *dentry; 1026 dentry = lookup_one_len(XAROOT_NAME, privroot, 1027 strlen(XAROOT_NAME)); 1028 if (!IS_ERR(dentry)) 1029 REISERFS_SB(s)->xattr_root = dentry; 1030 else 1031 err = PTR_ERR(dentry); 1032 } 1033 mutex_unlock(&privroot->d_inode->i_mutex); 1034 } 1035 1036 error: 1037 if (err) { 1038 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1039 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1040 } 1041 1042 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1043 if (reiserfs_posixacl(s)) 1044 s->s_flags |= MS_POSIXACL; 1045 else 1046 s->s_flags &= ~MS_POSIXACL; 1047 1048 return err; 1049 } 1050